We've been to the Hard Rock Hotel Las Vegas twice, and both times have been fantastic. Both times we were upgraded to a suite, even though we booked a regular room. The decor is fun & upbeat. Most rooms have balconies that overlook the amazing pool / grotto area. There are numerous restaurants (Nobu is a must-eat at least once), and a casino in the center of the hotel - which is nice because you aren't FORCED to walk through the casino to get to the rest of the hotel, like other places.
If you are coming to LV and do not have children, definitely stay here at least one time. It is a fun, upbeat, and reasonably priced hotel!